Field
Apparatuses and methods consistent with exemplary embodiments relate to a water-cooled power generator, and more specifically, to a separated coolant circulation structure for a water-cooled power generator in which a connector ring cooling circulation unit and a stator bar cooling circulation unit are separated so that a coolant is separately fed thereto, thereby improving the cooling efficiency of the high-capacity water-cooled generator.
Background of the Related Art
Usually, a high-capacity power generator (about 350 MW or more) employs a water-cooled armature winding, in which hollow wires are designed to have a hollow structure along a cooling path 1 within the armature (stator bar 100), as illustrated in FIGS. 1a and 1b, and a coolant flows in the hollow wires to cool the armature.
In the coolant circulation structure for the water-cooled power generator according to the related art, as illustrated in FIG. 1a, a cooling path 10 of the coolant extends from an upper winding at a turbine end B via a collector end A to a lower winding at the turbine end A. In the drawing, the arrow indicates a flow direction of the coolant.
According to the coolant circulation structure for the water-cooled power generator according to the related art, however, since the coolant which is primarily cooled while passing through the upper winding (flowing from the B side to the A side) is returned to the lower winding (flowing from the A side to the B side), the length of the cooling path 1 is prolonged, and thus the cooling efficiency is decreased.
If the length of the cooling path 1 is prolonged, as described above, there is a problem in that since a pressure loss across an inlet and an outlet of the coolant is increased, a pump load is usually increased for the purpose of the smooth flow of the coolant.
For reference, if the hollow wires, through which the coolant flows, are designed to be large so as to decrease the above-described pressure loss, the effective cross sectional area of copper forming the armature winding is decreased, thereby leading to a loss in electrical resistance.
In order to solve the above problems, Korean Patent No. 0695608, assigned to the applicant, is disclosed.
Korean Patent No. 0695608 solves the problems of the decreased cooling efficiency and the increased pump load of the related art, as illustrated in FIG. 1b, in which since the coolant is fed to a collector end E, divided into an upper winding 2 and a lower winding 3, and then discharged from turbine ends C and D, the cooling path is shortened to improve the cooling efficiency, and the pressure loss across the inlet and the outlet of the coolant is decreased to reduce the pump load.
However, Korean Patent No. 0695608 does not specifically disclose a cooling structure for a connector ring which is provided in the cooling path and has a high heating value. Although not shown in FIG. 2, the related art cools the connector ring by extending an upper line and a lower line of the collector end side to cool the stator bar 100 and the connector ring at the same time. However, since the stator bar and the connector ring are simultaneously cooled by the same lines, the cooling path is prolonged, and thus the problems of the decreased cooling efficiency and the increased pump load are not completely solved.